A storm system that could unleash mud and debris flows over slopes denuded by wildfires headed Tuesday for the Southland, where it’s expected to produce rain beginning Wednesday morning, National Weather Service forecasters said.
Between Wednesday and Thursday night, the system is expected to produce 1-2 inches of rain along the coast and in valley areas, and between 2 and 4 inches at the foothills and in the mountains, said NWS meteorologist Curt Kaplan, adding that some mountain areas could receive 5 inches.
The system, which originates in the Central Pacific, will combine with a colder system out of the Gulf of Alaska Friday and Saturday, generating rain through Saturday. Also expected is heavy rain through Saturday, with high surf and heavy winds expected.
Kaplan noted that this winter’s rain in the Southland is considerably more extensive than in 2018. He said that since Oct. 1, 2018, Downtown L.A had received 13.29 inches of rain compared to the previous year’s 1.89 inches and the normal, which is 8.54 inches.
Kaplan said the approaching rain could prompt flash flood watches and trigger some debris flows, along with the movement of some rocks and boulders, although it’s too early Tuesday morning to make a prediction with certainty.
The NWS forecast partly cloudy skies in L-A County Tuesday and highs of 51 degrees on Mount Wilson; 55 in Palmdale and Lancaster; 62 in Saugus; 63 in Avalon; 65 in Pasadena, Burbank, and at LAX; 66 in San Gabriel and Woodland Hills; and 67 in Downtown L.A. and Long Beach.
Partly cloudy skies were also expected in Orange County Tuesday along with highs of 49 on Santiago Peak; 61 on Ortega Highway at 2600 feet; 62 in San Clemente; 63 at Fremont Canyon; 64 in Newport Beach and Laguna Beach; 67 in Yorba Linda; 68 in Yorba Linda, Irvine and Mission Viejo; and 69 in Fullerton and Anaheim.
Rain is expected amid lower temperatures both Wednesday and Thursday. It will return to L.A. County in the form of showers Sunday.